There is no shortage of blog posts, YouTube videos, and social media posts created recently about the zettelkasten method. I’ve written several posts over the years myself. I continue be excited to see so much attention given to a working method with deep historical roots in the humanities and social sciences, one that I learned in high school and which has stuck with me since.
One topic that does not get a lot of attention in much of the content about zettelkasten, however, is the taking of so-called "fleeting notes," especially from printed books. A lot of content focuses on "literature notes" or "permanent notes." When fleeting notes are mentioned, the focus is often on taking such notes from digital sources like ebooks, news articles, PDFs, or even podcasts and videos. In this post, I want to describe my process for taking fleeting notes from printed books, including the system of marks I make in the margins of books and the app I have been using to get the marked text into my system.
What Are Fleeting Notes?
The term "fleeting notes" comes from author Sönke Ahrens’ book, How to Take Smart Notes, which is his account of the zettelkasten method as used by the German sociologist Niklas Luhmann. Though I have my issues with Ahrens’ rendering of zettelkasten, especially the essentially sole focus on Luhmann, Ahrens’ fleeting, literature, and permanent note terminology has caught on, so I will use them here for the sake of clarity. If you’d like to know more about the terminology I have tended to use for myself and with my students over the years, take a look at my post about getting started with zettelkasten.
Fleeting notes are the first step in the process of making notes for one’s zettelkasten. They are fleeting because they are meant to be temporary and, for many folks, disposable. These are the quick highlights we might make in a Kindle book, underlines in a PDF, or annotations in the margins of a printed book, perhaps even including a few short words to jog our memories later about why we marked the passage in question.
Fleeting notes are not meant to stand on their own, though many of us (myself included) do end up with piles of books and articles with highlights and annotations that sit for extended periods of time without doing much with them. Ideally, however, one would take these fleeting notes and process them into more complete literature notes. These are the notes we take that are more polished, that summarize in our own words the main argument and other relevant points from the book, article, etc. that we are reading. These, in turn, feed into our permanent notes where we begin to draw together multiple literature notes on the same topics or themes and use them to start making connections and writing up our own thoughts.
For understandable reasons, literature and permanent notes get a lot of attention. They are ultimately what we are driving at. They are the atomic building blocks that can be combined and recombined to propel our own creative endeavors. But the process all starts with those humble fleeting notes that we so often overlook. So, in the remainder of this post, I will share the system of marks I’ve devised over the years for taking fleeting notes from printed books and how I have been transferring the related text to my computer recently for further processing into literature notes.
Marking Printed Books For Fleeting Notes
In a nutshell, the basic process is to mark relevant passages and then use optical character recognition (OCR) on them for further processing on my computer. That sounds pretty straight forward, but I encountered several points of friction over the years that I’ve worked to overcome. Hopefully what I describe here will help you avoid those same sticking points.
As a graduate student, I initially fell back on the technique I had used as a high school debater and had taught other students as a coach in the 1990s. That involved placing brackets in the text around the passages to be used later as an evidence "card" to be cut out and pasted onto another sheet of paper into a "brief," which might be further cut and pasted into various structured arguments, such as an affirmative case or a counter plan or disadvantage to be read if my partner and I were taking the negative side. We would then further underline particularly salient portions of the extracted passage and write what we called a "tagline" that summarized the passage in our own words. It was an approach very similar to the "progressive summarization" method taught by Tiago Forte. This approach worked great for physically cutting and pasting (actually, we used Scotch tape), but did not work well when the ultimate goal was the digital cutting and pasting of that text after having OCR’d it. The underlining of physical progressive summarization would interfere with the OCR, as would the brackets too if I was not extremely careful to make sure they did not touch the printed text at all.
Next up, I moved to using highlighters for a hot minute, but this also didn’t last. The advantage to highlighters was that they did not interfere with the OCR process. They even came with the added benefit of allowing me to color code passages. But highlighters also turned out not to be ideal for reasons both immediate and more long term. First, if I wanted to extract a rather long passage, which I often did so as to surround the particularly salient bits in as much original context as possible, highlighting ended up being a big waste of ink. What’s more, the color coding did not turn out to be that useful when I scanned the text in black and white, which was necessary to create more manageable file sizes. In any case, I usually did not have enough colors to cover all the topics or themes I might be interested in from a given text. Nor would I want to switch colors that often while reading as it was just a hassle that slowed me down. I also found that I didn’t end up going back to consult those colors (which, like I said, were lost in the OCR process anyway) later when I was processing the notes on my computer. Second, I discovered that, depending on the ink, the highlights would fade over time. I might mark a text but not return to it for quite some time. (This is a problem, I know, but let’s be honest, it happens. None of us is perfect.) Even over the course of a year I noticed that highlights could fade significantly. Over longer periods they would disappear entirely in some cases. Not exactly a future proof method.
So, I needed a system of marking consistently that I would understand, that would be durable, but that would not interfere with the OCR process. I settled on a system that relies primarily on four marks and three short codes to mark and label key portions of the text in the margins of the book.
The three codes are MA, SA, and LS. They stand for Main Argument, Supporting Argument (which can include method and evidence or data), and Literature Sphere (i.e. the other literature or authors with which the current author is engaging). Marked passages with one of those codes are used to write up, in my own words, a summary of the work in question. All other marked passages without those codes are marked because they are relevant to my work, address an interesting or important theme, etc. So, for example, a passage of text that speaks to the author’s main argument will have in the margins a short, horizontal straight line at the start of the relevant passage (–), followed by the letters "MA," and then with another straight line (–) marking the end of the relevant passage. The same would be true for SA, LS, and for passages with no code.
In the remainder of this section, I provide some recent examples from a book I’m processing for a new project that is still in its early stages. This first example depicts a simple case of marking a passage with two short, horizontal lines but with no code applied.

But what if the relevant passage runs onto the next page? In that case, I will just put a downward facing arrow at the bottom corner of the first page and at the top corner of the following page. The end of the passage will be marked with a short, horizontal straight line as before. The arrow at the top of the next page is to eliminate any confusion about what that straight line might mean on the following page. Is it the start of a new marked passage? The arrow at the top tells me that any straight line that follows is an ending mark not a beginning mark.

In other instances, I might want to include some text, exclude a chunk of text, and then include more text later on the same or even the next page all in the same excerpted passage. In that case, the relevant passage will begin with the short horizontal straight line as usual, followed by a squiggly line (~) to mark the start of the portion to be excluded, another squiggly line to mark the re-start of the relevant text, and ending with a final straight horizontal line to mark the end of the overall excerpted passage. These markings correspond to how one might quote a long passage spanning more than one paragraph with certain portions excluded by using "[…]" to note the existence of those excluded portions. In this case, the portion between the squiggly lines is what would be marked in writing with the "[…]".

Finally, what if I want to take two passages that are immediately adjacent to one another but I want them separate because they speak to different codes or themes of interest–i.e. I want to keep those passages "atomic"? Using a series of three or more straight horizontal lines in a row can get confusing, making it tough to know where marked passages begin and end. In these cases, if two passages butt up against one another, I will note the end of the first and beginning of the next with a plus sign (-+-) where the horizontal line is longer than the vertical line.

And that’s it. Four marks and three main codes or labels prove to be remarkably flexible for marking up a printed text with minimal markings in the margins, handling most scenarios one might encounter (e.g. page spanning, adjacent passages, etc.), without having to switch pens or highlighters, in a way that retains meaning if one scans in black and white, and in a way that does not interfere with the OCR process. But how do I get those marked passages OCR’d for later processing?
Getting Marked Fleeting Note Text Into Your System
When I started using this system in preparation for my comprehensive exams and dissertation proposal research around fifteen years ago, I initially used a flatbed scanner and Adobe Acrobat Pro to scan and then OCR pages that had marked passages on them. There were three problems, however. First, it was a slow process. Second, it chained me to my desk in my home office. I tended to work a lot in those days at coffee shops or bookstores meaning that transferring passages and writing summaries of them had to wait until I got home. Third, it created too clear of a separation between reading and marking passages and transferring and processing those passages. What if I could scan passages as I read like I would mark them with a highlighter?
Well into my dissertation research I ended up buying a C-Pen scanner to do just that. The device was the size of a highlighter and allowed me to scan a line of text at a time, just like highlighting. It would vacuum up and OCR the text on the fly. I could then transfer the text via infrared connection to my Palm TX and write out a summary of the passage in my own words. Later, I would transfer the passages and summaries, each an individual plain text file, into a folder on my computer. Initially, I imported those into a custom Filemaker Pro database I had written. Later, I switched to having those files automatically imported into Evernote. In other cases, I would skip the Palm step and just transfer files directly from the scanner into that same folder and add the summaries using my computer keyboard instead.
Alas, the C-Pen I had–in fact, that I still have in a drawer along with the Palm TX too–was only compatible with Windows and thus was no longer part of my workflow after I switched to Mac in 2008. At that point, most of my work involved online sources of one kind or another and I didn’t have much of a need for large scale scanning and OCRing of text from physical books. Recently, however, a new project I’m starting on military conceptions of communication in the emergence and evolution of theories of information warfare has me looking at a number of primary and secondary sources for which no digital copies are available. I’m back to reading on "dead trees" as my friend and co-author Rob Gehl likes to say. Though there is a new generation of handheld pen scanners available, such as the ScanMarker, I haven’t tried them yet.
Instead, at the moment, I’ve been super impressed with a free iOS app called Highlighted. This app allows you to enter basic information about a source and then use your camera to take pictures of text from that source. It OCRs the text on the fly, allowing you to highlight those portions of text you want to keep, add a page number, and add a note. In the short screencast video below you can see how I’ve been using it on one of the books I’ve been processing for my new project.
After adding all the passages I have marked in the printed book, I can export them in Markdown format for further processing in another application like DEVONthink or Obsidian. I can export them in page number order (ascending or descending) or by time added (newest or oldest first). I usually opt for ascending page number order so the passages follow the flow of the book. I’ll admit that it’s not quite as seamless as my dissertation workflow with the old C-Pen back in the day. But for now, it does the trick and it’s free.
Conclusion
And that’s it! Four simple marks, three codes, and a free iOS app provide a great solution for taking fleeting notes from printed books. Again, of course our ultimate goal is to create those literature and permanent notes, what I tend to call "source briefs," "topic briefs," and "memos" in my eclectic mash-up of high school debate and qualitative research methods like grounded theory. But the core concepts are the same and it all starts with those "fleeting notes" we make in the margins with pens, highlighters, or sticky notes.
Inductive coding in qualitative research method. Source: https://delvetool.com/guide.
In my case, I wanted a streamlined system that required the use of only one pen, had as few marks and codes as possible, and did not interfere with the OCR process. What I developed more than fifteen years ago has served me well for my dissertation work, which led to several journal articles and my first book. It continues to work well today as I embark on a new project that has me looking much more at physical books than I have in the last several years.
I hope what I’ve described here will be of benefit to you in your work. Feel free to adopt this same system or to modify it as you see fit to meet your own particular needs. And if you do, write up a post or record a video and share it with me. I love to see how other people go about doing their work!